Influence of surface micro-oxidation on the formability of pure copper powders by selective laser melting

The absorption of laser energy by pure copper powders has a huge impact on the formation of high quality pure copper parts by selective laser melting. In this paper, surface modification technology was used to treat pure copper powder to improve the laser absorption effect of pure copper powder. It was found that modifying the surface of pure copper powder to generate a layer of CuO film effectively improved the absorption of laser energy by pure copper powder. Uniform and dense CuO films improved the quality of selective laser melting pure copper parts, which solved the problem of preparing pure copper powders for selective laser melting of high-density parts. The microstructure of selective laser melting high-density pure copper parts consisted of fine columnar and cellular crystals. The presence of subcrystals and dislocations was found in localized areas. The results of the physical phase analysis showed that the CuO phase existed in the parts prepared from the surface-modified pure copper powder, and the presence of the nano-CuO phase also enhanced, which effectively improved the microstructure and properties of the constituent selective laser melting pure copper parts.